Solar Orbiter observation of the ICME (bounded by the dashed vertical lines) and its driven shock event (solid vertical line) during the period from 2020 April 18 to 2020 April 21. Top panel: time profiles of the magnetic field vector measured by the Solar Orbiter/MAG instrument. Second and third panels: elevation (θ) and azimuthal (ϕ) angles of the magnetic field direction in the RTN coordinate system. Bottom panel: spectrogram of the normalized magnetic helicity σ_m using the Morlet wavelet method. Contour lines are drawn at levels of |σ_m| = 0.8.